1. Field of the Invention
The present invention relates to a fan apparatus, and particularly to a fan apparatus including a fan unit and a casing in which the fan unit is disposed.
2. Description of the Related Art
As one type of server, there is a blade server. The blade server is a computer system provided with one or more circuit boards called server blades. The server blades include electronic components such as an MPU (Micro Processing Unit), a memory, and/or a hard disk mounted thereon.
Each server blade is included in a chassis. The chassis is arranged in a rack cabinet. An example in which server blades are disposed in a chassis is shown in JP-A-2004-240967, for example.
In the blade server, electronic components are mounted in a high-density fashion, and a large amount of heat is generated by these electronic components. The heat that is generated by the components is likely to remain in the chassis. In order to radiate the heat from the interior of the chassis to the exterior of the chassis, the blade server is provided with a fan. Using this fan, hot air in the blade server is circulated to the outside, thereby cooling the electronic components disposed in the blade server.
Generally, a fan requires a large air flow and high static pressure in order to properly discharge air. A fan to be included in a blade server must be capable of discharging air with a large air flow and high static pressure. One type of fan that discharges air with a large air flow and high static pressure is a fan unit that includes a plurality of axial fans.
In some cases, a duct and a casing are attached to the fan. Using this configuration, the air discharged by the fan can be guided to various locations in the blade server. However, depending upon the configuration and structure of the duct, the casing, and the fan unit, the cooling properties of a fan apparatus provided by the duct, the casing, and the fan unit will vary. Accordingly, specific configurations and structures of the duct, the casing, and the fan unit are necessary to improve the cooling properties of the fan apparatus.